A structure of a convective torch of axisymmetric flame in combustion of a propane-air mixture was studied experimentally under the conditions of velocity perturbations on the nozzle section. The flow was visualized by a Mach-Zehnder interferometer and also using stroboscopic photography of the flame proper luminescence. Mean temperature distribution in a torch was studied using a Chromel-Alumel thermocouple. The obtained data show the presence of torroidal coherent vortex structures moving downstream that substantially enhance combustion processes and heat transfer in a torch.